1. Field of the Invention
The invention concerns a packaged effervescible mouthwash composition which generates fresh effervescence at the time of use.
2. The Related Art
Effervescent mouthwash compositions, especially carbonated mouthwash, have been recognized as having desirable and advantageous dental properties. Special packaging is usually required. For instance, U.S. Pat. No. 3,729,533 (Gold et al) discloses an effervescent composition packaged in a two-compartment container. The first of these compartments is intended to store an alkaline solution such as aqueous sodium bicarbonate. The second of the compartments is intended to store an acid solution. During storage, each of the components are maintained separate from one another to prevent premature reaction. Upon dispensing, the components mix and thereby release carbon dioxide.
U.S. Pat. No. 4,687,663 (Schaeffer) describes a toothpaste having semi-solid bicarbonate and semi-solid hydrogen peroxide-containing components, each extruded from separate compartments and placed in contact on a toothbrush. When the brush is applied to teeth and gums, immediate mixing of the components occurs with rapid evolution of oxygen and carbon dioxide. The combination of the ingredients is believed to kill bacteria responsible for gum disease.
U.S. Pat. No. 5,154,917 (Ibraham et al) reports a mouthrinse product comprising a multi-compartment bottle with liquids of different colors stored therewithin. One of the liquids is alkaline containing sodium bicarbonate/carbonate. A second of the liquids is an acidic solution formed of citric acid. These red and blue liquids, respectively, upon dispensing from the bottle combine to form a liquid admixture of yet another color.
In copending U.S. patent application. Ser. Nos. 07/954,847, now U.S. Pat. No. 5,289,950 and 07/954,848, now U.S. Pat. No. 5,252,312, both filed Sep. 30, 1992, there is disclosed a packaged effervescible composition containing sodium bicarbonate and hydrogen peroxide active material, each in separate compartments of a dual-compartment dispenser. The dispenser includes a closure system comprising an inclined crown portion, at least two pouring spouts extending upwardly from an upper surface of the crown portion and a cover for securement to the crown portion. The cover is provided with depending plugs to close the closure. Each pouring spout is preferably provided with a vent opening in addition to product orifices in the spouts. The orifices can be positioned close together on the crown, all of which assists in achieving control over pouring.
Among problems of the known art is the tendency of one or a mixture of the components to drain back into the compartments and thereby spoil the contents. Secondly, the user of the package is given insufficient visual guidance on how to dispense the components from the package. As a result, unwanted premature mixing of materials may occur during pouring. This leads to reaction of the hydrogen peroxide and sodium bicarbonate outside of the mouth with no beneficial oxygen evolution. Thirdly, known packaging for dispensing from a multi-compartment dispenser is not adapted for uniform pouring of the components into small-mouth cups of the type typically used for mouthwash.
Even with the improvements of the copending applications, there have remained certain problems. For instance, hydrogen peroxide has been identified as storage unstable in a transparent container when exposed to light. On the other hand, light-excluding opaque containers have proved to be unsatisfactory. Opacity hinders a person's ability to accurately and controllably dispense relatively equal volumes from a dual-compartment dispenser. Transparent walled containers also serve as a window function for gauging the amounts of liquid remaining in the dispenser.
A further problem with the technology reported in the copending applications is that the vent holes are only partially successful in preventing "glugging" and uneven pouring. The "glugging" problem arises when the dispenser is tilted beyond the horizontal, especially when the container is full and is turned upside down.
Another problem with the dispenser as disclosed in the copending applications concerns the relatively large cover which obscures, at least to some extent, a view of the pouring operation. Pouring requires a certain amount of careful control to assure dispensing of equal volumes of each of the components.
Accordingly, it is an object of the present invention to provide a packaged effervescible composition with improved stability against premature light-induced decomposition of hydrogen peroxide while at the same time maintaining visibility of the liquids to be dispensed.
It is another object of the present invention to provide a packaged effervescible composition that eliminates "glugging" even under the most acute circumstances.
It is still another object of the present invention to provide a packaged effervescible composition with an improved line-of-sight that is unincumbered by such features as the cover of the dispenser.
It is a further object of the present invention to provide a packaged effervescible composition wherein the package has improved stability against toppling over from the standing position.
These and other objects of the present invention will become more readily apparent upon consideration of the foregoing summary, drawings and detailed description.